Table 3 Quality assessment according to Newcastle–Ottawa of the included case–control studies
items | Lv et al. (2018) | Cheng et al. (2022) | |
|---|---|---|---|
Selection | Is the case definition adequate? | ★ | ★ |
Representativeness of the cases | ★ | ★ | |
Selection of controls | ★ | ||
Definition of controls | ★ | ★ | |
Comparability | Comparability of cases and controls on the basis of the design or analysis | ★★ | ★★ |
Exposure | Ascertainment of exposure | ★ | ★ |
Same method of ascertainment for cases and controls | ★ | ★ | |
Non-response rate | ★ | ★ | |
Grade | 9★ | 8★ | 9★ |